The present invention generally relates to the weaving art and, more specifically, relates to a new and improved construction of a so-called multiple longitudinal traversing shed weaving apparatus or loom, meaning a loom wherein a plurality of successive sheds are formed and retained to establish waves of sheds which travel longitudinally of the warp threads. Such type looms have also been referred to in the art as warp-wave looms, in order to distinguish the same from the type of loom using "weft waves" traveling transversely of the warp threads.
Generally speaking, the multiple longitudinal traversing shed weaving apparatus or loom of the present development is of the type comprising a weaving rotor which is provided with shed-retaining elements or members which retain the warp threads throughout a predetermined path, in their upper shed position or lower shed position and further is equipped with beat-up or beating elements which beat the inserted weft thread.
Multiple longitudinal traversing shed looms or warp-wave looms, as is known, form together with the so-called wave shed weaving machines, the species of multi-phase weaving machines of looms wherein there are continuously inserted a number of mutually stepwise shifted or staggered weft threads in likewise stepwise shifted and traveling sheds. While with the wave shed weaving machines the sheds are simultaneously multiply formed over the width of the fabric and migrate in the weft direction, in the case of the multiple longitudinal traversing shed weaving looms there is formed, in each case, a shed over the entire fabric width and the successively formed sheds simultaneously move in the direction of the warp thread.
During this migration of the sheds in the warp thread direction the formed sheds must be retained, so that the stepwise mutually displaced weft insertion can be accomplished. For this purpose there are used the so-called shed-retaining elements.
A first type of multiple longitudinal traversing shed weaving machine of the previously mentioned type has been disclosed in U.S. Pat. No. 2,742,058, wherein the weaving rotor is formed by alternately arranged polygonal warp thread-support disks and separation disks. The warp thread-support disks serve for both shed formation and also as shed-retaining elements and therefore, depending upon the desired weave, i.e. pattern to be woven, are arranged shifted through an angle. The warp threads extend from the warp beam, through a stationary reed, to the individual warp thread-supporting disks.
This state-of-the-art first type of multiple longitudinal traversing shed loom was not adopted in practice, and specifically, primarily because each weaving pattern change required restructuring of the weaving rotor.
To avoid this drawback there has been proposed in U.S. Pat. No. 3,848,642 a multiple longitudinal traversing shed loom wherein there is arranged forwardly of the region of the sheds a control means in order to laterally deflect each warp thread, according to a predetermined program, and therefore, to allocate a shed-retaining element which is responsible for the upper shed or lower shed. Each shed-retaining element possesses a thread support located at the height of the upper shed or lower shed. Each shed-retaining element is provided in each case for a multiplicity of warp threads, so that for instance during linen weave for warp threads come to bear in each instance upon each support.
With this prior art second type of multiple longitudinal traversing shed loom the weaving rotor need not be restructured each time there is a change in the cloth or fabric pattern which is to be woven, but on the other hand the beat-up elements, which are not particularly discussed in the aforementioned U.S. Pat. No. 3,848,642, must drop into the warp threads located in the upper shed position. This, in turn, can result in leasing errors which are also known in the case of wave shed weaving looms working with rotatable reeds. Additionally, the allocation of a multiplicity of warp threads in each case to a thread support leads to the undesirable result that the warp threads must be shifted over a relatively large path. In those instances where this displacement path reaches the range of the stroke of conventional shed-forming means, this can undesirably sensitively limit the output of such multiple longitudinal traversing shed loom.